Yup! you're right! The trees are from Seiken densetsu 3 The grass as well. I think that game has one of the best graphics on the SNES in this genre. We're planning to do the graphics ourselves in a later stadium, but until then we're using graphics from other games to test our engine.

About the scripting language: we created that language ourselves. That way we can put everything in it we need for the game, nothing more, nothing less. It has syntax-features from different other languages combined, like C++, Delphi, Basic, etc. We wrote a fast interpreter to interpret the scripts back into the game.
For the DialogEditor we developed a scripting language that's transparent to the user. Because dialogs in our game can be more complex, we decided to create a intuitive tool to design those dialogs. That's why there's a 'compiler' that checks the syntax of the Dialog the user created and compiles the dialog to the script-form we use in our game.

Coen